At present, sustainable development is a long-term target of human beings, enhancing energy efficiency and reducing energy consumption is becoming an increasingly important topic. In the communication field, how to enhance energy efficiency of devices and terminals is a key part for saving energy.
FIG. 1 illustrates an area repeated covered by several cells in prior art. The same area as shown in FIG. 1 is repeated covered by multiple cells, in which, cell B 120, cell C 130, cell D 140 and cell E 150 of Long Term Evolution (LTE) are completely covered by cell A 110. Cell A may be a Universal Mobile Telecommunications System (UMTS) cell, or a Global System of Mobile communication (GSM) cell or an LTE cell. Cell A provides basic radio coverage for the area and is an earliest deployed cell. With the increasing of user capacity, users are concentrated and user capacity is very high in some areas, and the user-concentrated area is just a user hot area, on where new cell devices need to be deployed to provide service for users in the hot area. For example, cell B 120, cell C 130, cell D 140 and cell E 150 are all hot cells, and the main objective of these hot cells is to improve user capacity, and provide more advanced access technology. Cell A seamlessly covers the area and provides service for the area, thereby is called completely covered cell. The coverage of hot cells is discontinuous.
User capacities of some hot areas change with time or by the turn of events. If a cell base station in these hot areas also works normally when there is no user capacity, much electric energy will be uselessly consumed, this is obviously conflicted with the sustainable development target. Therefore, a cell device of a hot area may be closed and provide no access service while there is no user capacity, and be opened and provide access service for users at air interface while there is user capacity, thus to achieve the purpose of energy saving and consumption reduction.
There are several methods for closing a cell device at the present time. In one method, when a cell device will be closed is determined by a central operation and maintenance device. Some information is configured in the operation and maintenance device in advance, and when a close condition is satisfied, the operation and maintenance device determines that the cell device will be closed. For example, operators pre-set some closing strategies in an operation and maintenance device, when the closing strategies are satisfied, the operation and maintenance device transmits a signaling to request a cell device to stop transmitting and receiving air signals, thus putting the cell device into a close state. In another method, a cell of a hot area reports its user capacity to the operation and maintenance device, when the user capacity is lower than a threshold for a period of time, the operation and maintenance device transmits a command to make a cell device of the hot area be closed. After the cell device is closed, the cell transmits a message to neighboring cells for notifying them that the cell is in a closed state. In yet another method, a cell device determines when to close itself. Operators pre-set some closing strategies in a cell device of a hot area, and when the closing strategies are satisfied, the cell device is automatically closed and transmits a message to neighboring cells for notifying them that the cell is in a close state.
After the cell device in a hot area is closed, the cell providing basic radio coverage provides service for users in the area. When the number of users in the hot area increases, and when user capacity of the cell providing basic radio coverage exceeds the threshold, the cell device in the hot area needs to be opened. Open methods include the following.
In a first method, open strategies are pre-set in an operation and maintenance device, and when an open condition is satisfied, the operation and maintenance device transmits a command to make the cell device in the hot area be opened.
In a second method, open strategies are pre-set in a cell device of a hot cell (called as hot cell device hereinafter for simplification), and when an open condition is satisfied, the hot cell device is automatically opened and provides service for users.
In a third method, when a cell providing basic radio coverage detects that user capacity of the cell exceeds a certain threshold, the cell providing basic radio coverage transmits a command to a hot cell device, and requires the hot cell device to open and provide service. Then some users in the cell providing basic radio coverage are switched to the new opened cell.
In a fourth method, an Interference over Thermal (IoT) is monitored after the cell device of a hot area is closed. The IoT is a ratio of received interference energy to thermal noise. After the hot cell is closed, terminals are served by the cell providing basic radio coverage, and signals of the terminals are interference signals to the closed cell. The larger the user capacity and the closer the proximity to the hot cell device, the more serious the interference and the higher the IoT. It can be seen that the higher IoT means the user capacity near the hot cell is larger. When the user capacity of the cell providing basic radio coverage increases, a device in the cell providing basic radio coverage (called as basic coverage cell device hereinafter for simplification) requests the cell device of a hot area to report the IoT, and then according to the IoT determines which hot cell devices to be opened.
It can be seen from above-mentioned methods for managing hot cell devices, there are at least following problems in the prior art.
At first, in the same region, there is more than one hot area and more than one corresponding hot cell device. When the user capacity of the cell providing basic radio coverage exceeds a threshold, the cell providing basic radio coverage transmits a message to all hot cell devices and commands all hot cell devices to open. However, users in the cell providing basic radio coverage can be switched to one or part of the hot cells, and there may be no user capacity in other hot cells, thereby when all hot cell devices are open will lead to energy wasting.
Secondly, some hot cells have larger coverage, and others have smaller coverage. If an IoT monitored by a hot cell is higher, but coverage of the hot cell is smaller, then users can be covered by another hot cell, and then an inappropriate cell device can be opened by utilizing technical solutions in the prior art.
Thirdly, when a cell device of a hot area receives an open command, the cell device opens capabilities of whole cell, for instance, opens all antenna ports. However in the ordinary course of events, the number of users to be switched to a hot cell is not larger at the beginning, and the capabilities of whole cell are all opened in the prior art conflicts with the target of energy saving. If the hot cell devices are configured to gradually open device capabilities, when a larger numbers of users in the cell providing basic radio coverage need to be switched to hot cells, requirement of the cell providing basic radio coverage (called as basic coverage cell hereinafter for simplification) can not be satisfied.
It is obvious that, the conventional methods for managing hot cell devices can cause energy wasting.